The present invention relates to film construction wherein biaxially oriented polypropylene is utilized as the base layer. More specifically, the present invention relates to a film construction which is useful as shielding in the manufacture of coaxial and other transmission and communication cables and also in the manufacture of flexible packaging materials.
In the past, such film constructions have been made by utilizing a base layer of a material such as polyethylene terephthalate and coating each side of the base layer with an adhesive material. After coating, aluminum foil or some other material can be bonded to the film construction by means of the adhesive layers. The present invention provides a new construction which has sufficient strength and toughness (biaxially oriented polypropylene provides structure and toughness as does polyethylene terephthalate) without the use of adhesive materials and which can be formed by a one-step thermal lamination process which is simpler and less expensive than the two-step coating method described above.